Process and apparatus for dampening the plate cylinders of lithographic and analogous presses



Dec. 24, 1935. GOED] 2,025,045

PROCESS AND APPARA FOR DAMPEN THE PLATE CYLINDERS OF LITHOGRAPHIC AND ANALOGOUS PRESSES Filed 001;. 21, 1930 /a E /4 /e 25 E as 24 6 I E 1 nvwszvron /7 N 6.60ED/KE A 7' TORIVE Y Patented Dec. 24, 1935 UNITED STATES PATENT OFFICE "401m G. Goedike, San Antonio, Tex.' Application October 21, 1930, Serial No. 490,311

Claims.

(Granted under the act of March 3, 1883, as amended April 30, 1928; 3'70 0. G. 757) This invention described herein may be manufactured and used by or for the Government for Governmental purposes, without payment to me of any royalty thereon.

This invention relates to a method of, and means for dampening the plates employed on lithographic presses for use in ofi-set lithographic and analogous printing operations and has for its primary object the provision of a method and apparatus whereby the plates, preferably in the form of a hollow cylinder, are dampened by a process of condensation of moisture which is induced by the chilling of the plate cylinders, the amount of moisture condensed on the plates being controlled by the temperature to which the plates are lowered.

Another object of my invention is to provide an apparatus for injecting cold air, gas, or other suitable liquid or gaseous substance into the plate cylinders of lithographic presses so as to chill the same in order to induce condensation of moisture thereon for dampening purposes.

A further object of my invention is to provide a leak-proof plate cylinder for lithographic and analogous printing presses which is adapted to contain a .cooling medium such as cold air, gas, or other suitable liquid or gaseous substance.

A still further and important object of my invention is to provide an apparatus which may be attached to one end of a plate cylinder or cylinders of lithographic presses for chilling the plate cylinder so as to cause the dampening thereof by condensation of moisture without interfering with the operation of the working parts on the other side of the press.

Ordinarily in making prints from lithographic and analogous printing operations, a moistening apparatus using water or other substance is employed for dampening the plates. This entails a substantial delay after the making of each print, requires more labor than does the method of the present invention and provides a very inefiicient method of dampening.

These disadvantages are avoided by this invention which provides an apparatus for dampening the plates used on lithographic and analogous printing operations by the automatic condensation of moisture. This result is obtained by chilling or lowering the temperature of the plates between substantially 40" F. and to the freezing point thereof 32 F. which is considerably below the dew point of the normally surrounding atmosphere of the press room where the press is employed, thereby eliminating the use of the present moistening devices, increasing the number of prints which may be produced in a given time, making the operation of producing the prints more eificient and economical and reducing the amount of labor required and cost of mak- 6 ing the prints.

In order that my invention may be readily understood reference is had to the accompanying drawing in which corresponding parts are indicated by the same reference characters and 10 in which:

Fig. 1 is a side elevation partly in section of my improved dampening apparatus applied to the plate cylinder of a lithographic press; and

Fig. 2 is a cross sectional view taken on line 18 2-2 of Fig. 1.

In carrying out my invention, the plate I which in the present illustration is shown as a hollow cylinder of a lithographic or analogous printing press is closed at one end by a head 2 20 containing a journal 3, while the other end of the plate I is provided with a head 4 containing a hollow journal 5, the purpose of which will hereinafter be described. The journals 3 and 5 are mounted in the bearings 6 formed in a frame 1 of any suitable lithographic press, that is to say that the outer end of each journal 3 and 5 extends through and snugly fits in the adjacent part of the frame 1. Each end of the plate cylinder l is provided with circumferentially arranged gear teeth 8 for rotating the plate cylinder I, these gear teeth 8 being adapted to intermesh with other gearing of the press (not shown). Adjacent the hollow journal 5 and enclosing the outer end thereof is a housing 9 which is attached to the outer side of the frame I by any suitable means such as bolts [0. Any suitable leak preventing means as a resilient washer ll may be inserted between the frame I and housing 9 as shown. 4

The housing 9 is provided with a screw threaded opening [2 which is of substantially the same diameter as the opening in the hollow journal 5. This opening l2 of the housing 9 engages the screw threaded end l3 of an exhaust or overflow pipe M, the other end l5 of the exhaust or overflow pipe 14 being connected to a T 16. The T 16 is threadedly connected to a compressor ll of a conventional cooling system by means of pipe l8. The T It may be also connected to a source of warming medium by means of the valve Hi. The compressor ll of the cooling system is connected to one end of a condenser 20, the other end of the condenser 20 being connected to a liquid receiver 20'. The cooling medium is constrained in its motion from the liquid receiver 20' to the plate cylinder I by means of the piping 2I expansion or control valve 22, and inlet piping 23. The inlet piping 23 pentrates the T I6 and forms a leak proof joint therewith by being welded thereto asat 24. The said piping 23 continues on through exhaust or overflow pipe I4, housing 9 and journal 5 into the cylindrical plate I where it branches into spray pipes 25 for directing the cooling fluid closely adjacent the inner surface of the rotatable plate cylinder I. The external diameter of the inlet piping 23 is small enough to form a return passage-way 26 between itself and juxtaposed constraining walls.

In chilling the plate cylinder I for causing the dampening thereof by the condensation of moisture thereon the compressor I1 forces the cooling medium or refrigerant under a high pressure into the condenser 20. The cooling medium or refrigerant then flows from the condenser 20 into the liquid receiver 20' from where it is conducted by the piping 2|, through the expansion or control valve 22 and inlet piping 23 into the interior of the plate cylinder I. The plate cylinder I when rotated by the gears 8 keeps the cooling medium stirred and distributed around its interior to chill the plate cylinder I below the dew point of the atmosphere and cause a condensation of moisture to be formed on its exterior surface 21 thereby providing a dampened surface. The cooling medium finally works its way back through the passage-way 26, that is the space around the inlet piping 23 of the hollow journal 5, through the housing 9 into the exhaust or overflow pipe I 4 and from there into the T I 6, the cooling medium then flowing through the pipe I8 and entering the suction port ll of the compressor I! of the cooling system.

It will thus be seen that I have provided a highly novel, simple and efficient process and apparatus for dampening the plate cylinders of lithographic and analogous printing presses that is well adapted for all the purposes designated. Even though I have herein shown and described my apparatus for carrying out the invention as comprising certain structural elements it is nevertheless to be understood that changes may be made therein without departing from the spirit or scope of my invention.

Having described my invention what I claim as new and wish to secure by Letters Patent is:

1. An apparatus for chilling a hollow cylindrical lithographic plate substantially below the dew point of the atmosphere surrounding the plate for producing a film of moisture on the exterior surface thereof comprising a cooling system containing a fluid medium, a chamber, and piping including an inlet pipe for providing a passage-way for leading the fluid medium from said cooling system into the interior of said plate, means forming a passage-way for leading said fluid medium out of said plate into said cooling system said means comprising a hollow journal on said 5 plate, a housing containing an aperture surrounding one end of said hollow journal, an ex haust pipe having one of its ends connected to the aperture of said housing, a T connected to the other end of said exhaust pipe, and piping 10 connecting said T with said cooling system, said hollow journal, exhaust pipe and said T surrounding said inlet pipe, and a valve on said T for insertion of warm medium into the plate cylinder. 15

2. An apparatus for chilling a hollow cylindrical lithographic plate substantially below the dew point of the atmosphere surrounding the plate to produce a film of moisture on the exterior surface thereof comprising a cooling system includ- 20 ing means in the form of a pipe mounted within and independent of said plate and providing a passage-way for leading a cooling medium from said cooling system into the interior of said plate and means enclosing said pipe for providing a 25 passage-way for said medium out of said plate.

3. The process of dampening a hollow cylindrical plate of lithographic and analogous printing presses, which comprises chilling a planographic plate substantially below the dew point of the normally surrounding atmosphere thereof to produce a condensation of moisture on the outer surface of said plate by spraying a cooling medium on the interior thereof.

4. In a combination of apparatus of the character described having a cooling element connected to. the low pressure side of a refrigerating system, a lithographic surface, means for substantially reducing the temperature of said surface to the dew point of the atmosphere sur- 40 rounding the surface to produce a film of moisture thereon, the sole source of said film of moisture comprising the atmosphere surrounding said surface, a shaft mounting said surface and rotatable therewith, said shaft provided with an in- 45 let and outlet for refrigerant.

5. The method of dampening the printing surface of plate cylinders of lithographic or analogous printing presses, which consists of circulating a refrigeranting medium at low pressure in 60 a closed path within said plate cylinder to absorb heat therefrom and to reduce the temperature of said printing surface below the dew point of the atmosphere surrounding it, to condense moisture on said surface, and using the atmos- I55 phere surrounding said cylinder as the sole source of said condensation of moisture.

JOHN G. GOEDIKE. 

